Chemokines are chemotactic cytokines that are released by a wide variety of cells to attract macrophages, T cells, eosinophils, basophils and neutrophils to sites of inflammation and they also play a role in the maturation of cells of the immune system. Chemokines play an important role in immune and inflammatory responses in various diseases and disorders, including asthma, rhinitis and allergic diseases, as well as autoimmune pathologies such as rheumatoid arthritis and atherosclerosis. Chemokines are small 70 to 80 amino acid proteins with well-characterized three-dimensional structures, usually stabilized by two disulfide bridges. They are divided into four families on the basis of pattern of conserved cysteine residues.
Chemokine receptors have been designated such as, CCR1, CCR2, CCR2A, CCR2B, CCR3, CCR4, CCR5, CCR6, CCR7, CCR8, CCR9, CCR10, CXCR1, CXCR2, CXCR3, and CXCR4 and therefore agents which modulate these receptors may be useful in the prevention and treatment of diseases as mentioned above.
One of them, the C—C chemokines family, includes potent chemoattractants of monocytes and lymphocytes such as RANTES (Regulated on Activation, Normal T Expressed and Secreted), eotaxin, MIP-1α and MIP-1β (Macrophage Inflammatory Proteins) and human monocyte chemotactic proteins 1-3 (MCP-1, MCP-2 and MCP-3). More specifically, C—C chemokine receptor 5 (CCR5), a β-chemokine receptor with a seven-transmembrane-protein structure, was found to serve as a coreceptor for non-syncytium-inducing or macrophage-tropic HIV-1 (R5 viruses). It was also established that CCR5 is the principal chemokine receptor required for the entry of HIV into the cell during primary infection. Therefore, interfering with the interaction between the viral receptor CCR5 and HIV can block HIV entry into the cell. It would therefore be useful to provide novel compounds which are modulators of chemokine receptor activity.